The long-term objectives of the proposed research program are to provide the instrumentation required to perform minimally invasive procedures for safely dilating or occluding the lumens of canals, ducts or vessels that are located almost anywhere in the body. The procedures will not require the introduction of foreign materials into the body, materials that can sometimes cause serious side effects, and in many cases it will be possible to perform them on an outpatient basis. While the dilations and occlusion that are produced are likely to be long lasting, the procedures can be repeated if necessary. The instrumentation will consist of microwave generators operating in the 5800 75 MHz frequency band, and microwave catheters designed to produce biological stents or occlusions in various anatomical locations. The specific aims are to fabricate a prototype 5800 MHz solid-state generator, and microwave catheters designed for enlarging the lumens of bile and pancreatic ducts and of peripheral arteries, for occluding varicose veins. PUBLIC HEALTH RELEVANCE: The instrumentation that would result from the proposed program would enable physicians to safely enlarge the diameter of many important human canals, ducts, and vessels that are narrowed by disease, or to close them as is sometimes necessary. The physicians will be often be able to accomplish this on an outpatient basis and without having to introduce foreign materials into the body, materials that can sometime cause serious side effects. [unreadable] [unreadable] [unreadable]